Air conditioner outdoor unit drive control unit

ABSTRACT

When an outdoor machine  2  includes a signal line connector  21  for receiving ON/OFF signals for a compressor, an outdoor machine drive control unit  30  of an air conditioner includes an inverter device  32  for supplying power variable in frequency to the compressor  22,  and a control device  33  for controlling the inverter device  32  to gradually increase the number of revolutions of the compressor  22  when the ON/OFF signal for the compressor received through the signal line connector  21  changes from the OFF condition to the ON condition. The air conditioner outdoor machine drive control unit  30  enables to construct an inverter-type air conditioner by using a general heat-pump-type indoor machine and merely mounting it in an outdoor machine.

TECHNICAL FIELD

This invention relates to a separate-type air conditioner whose outdoormachine includes a signal line connected portion for receiving ON/OFFsignals of its compressor, and more particularly, to a outdoor machinedrive control unit in the air conditioner for power-controlling anddriving its compressor in response to ON/OFF signals from its indoormachine.

BACKGROUND ART

Separate-type air conditioners made up of an outdoor machine and anindoor machine involve ones of a so-called general heat-pump system inwhich a compressor constant in rotational speed is controlled in ON/OFFmotion in response to the air-conditioning load, and ones of a so-calledinverter system in which the compressor is controlled in power inresponse to the air-conditioning load. Among them, the inverter systemhas advantages in saving energy, enabling stepless, highly responsivespeed control, enabling adjustment of the speed of a general-purposemotor without the need for any auxiliary device, requiring only a smallstart current for the motor, and so forth.

Then, there was an attempt to remodel a general heat-pump-type airconditioner to an inverter-type air conditioner.

However, due to a large difference in control method between them,remodeling was not easy. Structure of a general heat-pump-type airconditioner the invention is directed to will be explained below indetail, clarifying differences from an inverter-type air conditioner.

FIG. 17 is a diagram of a control circuit of a general heat-pump-typeair conditioner. In the air conditioner, an outdoor machine 1 and anindoor machine 2 are connected by a plurality of crossover lines 3. Theindoor machine 1 includes a power source connector terminal 11 and anindoor-side connector terminal 13. The power source connector terminal11 includes power source line connectors L, N and a grounding lineconnector E. The indoor-side connector terminal 13 includes a powersource line connector N, first signal line connector for transmittingON/OF signals for the compressor, second signal line connector fortransmitting ON/OFF signals for an outdoor fan, third signal lineconnector for transmitting ON/OFF signals to switch a four-way valve tothe cooling side or the heating side, and grounding line connector E.

The power source line connector N of the power source connector terminal11 is directly connected to the power source line connector N of theindoor-side connector terminal 13. The power source line connector L ofthe power source connector terminal 11 is connected to the first, secondand third signal line connectors of the indoor-side connector terminal13 via a relay contact 18 a for the compressor, relay contact 18B forthe outdoor fan and relay contact 18C for the four-way valve, whichconstitute an indoor controller 12. The indoor controller 12 includes amicrocomputer unit (hereinafter abbreviated MCU) 14, and it isconfigured to control an indoor fan 15 and to control ON/OFF states ofthe relay contacts 18A, 18B and 18C in accordance with the roomtemperature detected by a temperature sensor 16, temperature of anindoor heat exchanger detected by a temperature sensor 17, and so on.

On the other hand, the outdoor machine 2 includes a compressor 22connected to the outdoor-side connector terminal 21, outdoor fan 23 andfour-way valve 25. The outdoor-side connector terminal 21 includes apower source line connector N, first signal line connector for receivingON/OFF signals for the compressor, second signal line connector forreceiving ON/OFF signal for the outdoor fan, third signal line connectorfor receiving ON/OFF signals to switch the four-way valve to the coolingside or the heating side, and grounding line connector E, which areconnected to corresponding connectors in the indoor-side connectorterminal 13 by a plurality of lines.

In the outdoor machine 2, one end of the compressor 22 is connected tothe first signal line connector, and the other end there of is connectedto the power source line connector N. Further, a phase-advance coilterminal is connected to the power source line connector N via aphase-advance capacitor. One end of the outdoor fan 23 is connected tothe second signal line connector, and the other end there of isconnected to the power source line connector N. Further, a phase-advancecoil terminal is connected to the power source line connector N via aphase-advance capacitor 24. One end of the four-way valve 25 isconnected to the third signal line connector, and the other end thereofis connected to the power source line connector N.

In the above-explained structure, MCU 14 forming the indoor controller12 controls the indoor fan 15 to drive or stop it in accordance with adrive mode instructed from outside, temperatures detected by thetemperature sensors 16, 17, and so on, and controls ON/OFF conditions ofthe relay contacts 18A, 18B and 18C. Its ON/OFF signals are transmittedto the outdoor machine 2 via the crossover lines 3. Thereby, driving orstopping the compressor 22, driving or stopping the outdoor fan 23 andenergizing or deenergizing the four-way valve 25 are controlled toeffect known heating operation, cooling operation or defrostingoperation.

In contrast, an inverter-type air conditioner, the present invention isnot directed to, is roughly explained below, omitting illustrationthereof in a drawing.

An instruction from a remoter controller and a signal from a temperaturesensor are arithmetically processed by MCU forming a indoor controller,and driving materials except for the ventilation amount of the indoorfan are transmitted in form of a serial signal to the outdoor machinevia crossover lines. A source voltage supplied to the outdoor machine isconverted into a direct current by a converter generically named aninverter device, and becomes a pseudo three-phase alternating current inthe inverter portion. The serial signal supplied from the indoorcontroller as the drive instruction signal is decoded in content by MCUforming the outdoor controller, and mixed and operated with informationfrom sensors of the outdoor machine. Then, a decided actual drivefrequency signal is supplied as a drive signal to the inverter portion.the inverter portion switches a transistor module with the drive signal,and outputs it as a pseudo three-phase alternating current to thecompressor.

As explained above, the general heat-pump-type air conditioner and theinverter-type air conditioner are different in indoor machine from theviewpoint of structure and way of signal processing, also in outdoormachine, and also in transmitted signal. Therefore, it has beenconsidered difficult as a system to remodel a general heat-pump-type airconditioner to have functions of an inverter-type air conditioner.

The invention has been made taking these circumstances intoconsideration, and its object lies in providing a outdoor machine drivecontrol unit in an air conditioner, which makes it possible to constructan inverter-type air conditioner by using a general heat-pump-typeindoor machine unchanged and merely mounting it in the outdoor machine.

Disclosure of Invention

An outdoor machine drive control unit for an air conditioner accordingto the invention is characterized in an outdoor machine drive controlunit for an air conditioner of a separate type having a signal lineconnector provided in an outdoor machine to receive an ON/OFF signal fora compressor exclusively, comprising: an inverter device for supplyingthe compressor with power variable in frequency; and a control devicefor controlling the inverter device to gradually increase the number ofrevolutions of the compressor when the ON/OFF signal for the compressorreceived through the signal line connector changes from the OFFcondition to the ON condition.

Further, an outdoor machine drive control unit for an air conditioneraccording to the invention is characterized in an outdoor machine drivecontrol unit for an air conditioner of a separate type having a signalline connector provided in an outdoor machine to receive an ON/OFFsignal for a compressor exclusively, comprising: an inverter device forsupplying the compressor with power variable in frequency; and a controldevice for controlling the inverter device to increase the number ofrevolutions of the compressor to a preset number of revolutions when theON/OFF signal for the compressor received through the signal lineconnector changes from the OFF condition to the ON condition.

In case of these outdoor machine drive control units in airconditioners, the control device may control the inverter device so asto gradually decrease the number of revolutions of the compressor whenON/OFF signals for the compressor change from the ON condition to theOFF condition.

Alternatively, the control device may control the inverter device so asto decrease the number of revolutions of the compressor to a minimumnumber of revolutions lower than a preset number of revolutions by apredetermined value when ON/OFF signals for the compressor change fromthe ON condition to the OFF condition.

When decreasing the number of revolutions of the compressor to theminimum number of revolutions, the control device Additionally, thecontrol device decrease the number of revolutions gradually.

An outdoor machine drive control unit for an air conditioner accordingto the invention is characterized in an outdoor machine drive controlunit for an air conditioner of a separate type having a signal lineconnector provided in an outdoor machine to receive an ON/OFF signal fora compressor exclusively, comprising: an inverter device for supplyingthe compressor with power variable in frequency; and a control deviceincluding a timer means for cumulatively counting the duration of timeof the ON condition after the ON/OFF signal for the compressor changesfrom the OFF condition to the ON condition so as to increase or decreasethe number of revolutions of the compressor depending on the length ofthe duration of time of the ON condition.

With the structure summarized above, it is possible to construct aninverter-type air conditioner by using a general heat-pump-type indoormachine unchanged and merely mounting it in the outdoor machine.

An outdoor machine drive control unit for an air conditioner accordingto the invention is characterized in an outdoor machine drive controlunit for an air conditioner of a separate type having a signal lineconnector provided in an outdoor machine to receive an ON/OFF signal fora compressor exclusively, comprising: an inverter device for supplyingsaid compressor with power variable in frequency; and a control deviceincluding a timer means for cumulatively counting the duration of timeof the OFF condition since said ON/OFF signal for the compressor changesfrom the OFF condition to the ON condition until returning to the ONcondition, so as to increase or decrease the number of revolutions ofsaid compressor after returning to the ON condition, depending on thelength of said duration of time of the OFF condition.

In this case, the control device may control the inverter device so asto increase the number of revolutions of the compressor when theduration of time of the OFF state exceeds a preset value. A plurality ofsuch preset values different in value may be determined.

With the structure summarized above, in addition to the effect that aninverter-type air conditioner can be made by using a generalheat-pump-type indoor machine unchanged and merely mounting it in theoutdoor machine, also obtained are the effects that the air conditionercan be started in a frequency meeting the desired power and intermittentdriving can be prevented.

An outdoor machine drive control unit for an air conditioner accordingto the invention is characterized in an outdoor machine drive controlunit for an air conditioner of a separate type having a signal lineconnector provided in an outdoor machine to receive an ON/OFF signal fora compressor exclusively, comprising: an inverter device for supplyingthe compressor with power variable in frequency; a temperature sensorfor detecting temperature of a refrigeration cycle component provided inthe outdoor machine; and a control device for controlling the inverterdevice to increase or decrease the number of revolutions of thecompressor in response to the temperature of the refrigeration cyclecomponent detected by the temperature sensor when the ON/OFF signal forthe compressor exhibits the ON condition.

In this case, the control device may control the inverter device toreduce the difference between the detected temperature of the coolingcycle member and the preset reference temperature.

With the construction summarized above, it is possible to construct aninverter-type air conditioner by using a general heat-pump-type indoormachine unchanged and merely mounting it in the outdoor machine.

An outdoor machine drive control unit for an air conditioner accordingto the invention is characterized in an outdoor machine drive controlunit for an air conditioner of a separate type having a first signalline connector for receiving an ON/OFF signal for a compressorexclusively, a second signal line connector for receiving an ON/OFFsignal for an outdoor fan exclusively, and a third signal line connectorfor receiving an ON/OFF signal for switching a four-way valve to acooling side or a heating side exclusively, which are provided in anoutdoor machine, comprising: an inverter device for supplying thecompressor with power variable in frequency; and a control deviceincluding a microcomputer for controlling output frequency of theinverter device, driving or stopping of the outdoor fan and switching ofthe four-way valve in response to a combination of ON/OFF conditions ofthe ON/OFF signals received by the first, second and third signal lineconnectors.

In this case, when the ON/OFF signal of the compressor is ON, the ON/OFFsignal of the outdoor fan is ON, and the ON/OFF signal of the four-wayvalve changes from the heating side to the cooling side, the controldevice may control the inverter device to increase the number ofrevolutions of the compressor to a preset number of revolutions for thedefrosting drive mode.

Additionally, after the control device increases the number ofrevolutions of the compressor to the preset number of revolutions forthe defrosting drive mode, when the ON/OFF signal of the compressor isON and the ON/OFF signal of the four-way valve returns in status to thecooling side to the heating side, the control device may control theinverter to drive for a predetermined time under a number of revolutionslower than its number of revolutions before the four-way valve changesfrom the heating side to the cooling side, and to switch the four-wayvalve from the cooling side to the heating side after driving thecompressor under the lower number f revolutions for the predeterminedtime.

With the structure summarized above, it is possible to construct aninverter-type air conditioner by using a general heat-pump-type indoormachine unchanged and mounting it in an outdoor machine and to drive inthe defrosting mode similarly to an existing inverter-type airconditioner.

Moreover, the control device may include a first microcomputer forcontrolling the inverter device exclusively, and a second computerconnected to the first, second and third signal line connectors totransmit control signals to a four-way valve driving device, an outdoorfan driving device and the first microcomputer in accordance with ON/OFFsignal received through the signal line connectors.

This structure additionally provides the effect that the major componentcan be assembled in two divisional parts to make it much easier to mountit in any of various kinds of outdoor machines different in size andconfiguration.

An outdoor machine drive control unit for an air conditioner accordingto the invention is characterized in an outdoor machine drive controlunit for an air conditioner of a separate type having a first signalline connector for receiving an ON/OFF signal for a compressorexclusively, a second signal line connector for receiving an ON/OFFsignal indicating whether the difference of the room temperature from apreset temperature is larger than a predetermined value or not, and athird signal line connector for receiving an ON/OFF signal for switchinga four-way valve to a cooling side or a heating side exclusively, whichare provided in an outdoor machine, comprising: an inverter device forsupplying the compressor with power variable in frequency; and a controldevice including a microcomputer for controlling driving or stopping ofthe outdoor fan, switching of the four-way valve and the inverter devicein response to a combination of ON/OFF conditions of the signalsreceived by the first, second and third signal line connectors.

In this case, the control device may decrease the number of revolutionsof the compressor by a predetermined value when it is detected from theON or OFF condition of the signal through the second signal lineconnector that the difference of the room temperature from the presettemperature is not larger than the predetermined value.

Additionally, the control device may decrease the number of revolutionsof the compressor by a predetermined value when it is detected from theON or OFF condition of the signal through the second signal lineconnector that the difference of the room temperature from the presettemperature is not larger than the predetermined value, and maythereafter increase the number of revolutions of the compressor by apredetermined value when it is detected from the ON or OFF condition ofthe signal through the second signal line connector that the differenceof the room temperature from the preset temperature is larger than thepredetermined value.

Alternatively, the control device may decrease the number of revolutionsof the compressor by a first predetermined value when it is detectedfrom the ON or OFF condition of the signal through the second signalline connector that the difference of the room temperature from thepreset temperature is not larger than the predetermined value, and maythereafter increase the number of revolutions of the compressor by asecond predetermined value smaller than the first predetermined valuewhen it is detected from the ON or OFF condition of the signal throughthe second signal line connector that the difference of the roomtemperature from the preset temperature is larger than the predeterminedvalue.

With this arrangement, it is possible to construct a inverter-type airconditioner by using a general heat-pump-type indoor machine unchangedand mounting it in an outdoor.

The outdoor machine may include a plurality of sets of signal lineconnectors, each set including the first, second and third signal lineconnectors, and the control device controls output frequency of theinverter device, driving or stopping of the outdoor fan and switching ofthe four-way valve in response to a combination of ON/OFF conditions ofthe ON/OFF signals through the first, second and third signal lineconnectors.

With this arrangement, it is possible to construct a inverter-type airconditioner by using a general heat-pump-type indoor machine unchangedit is and mounting it in an outdoor and to reduce changes in roomtemperature.

In the outdoor machine control unit in an air conditioner, the controldevice may include a power converter means for converting an a.c.voltage from an a.c. power source into a d.c. voltage, a reactorconnected in series to one end of the power converter means nearer tothe a.c. power source, and a short-circuiting means for short-circuitingthe a.c. power source near a zero cross point of an a.c. voltagewaveform via the reactor for a predetermined period.

This structure also provides the effect of improving the source powerfactor.

Alternatively, in the outdoor machine control unit in an airconditioner, the control device may include a power converter means forconverting an a.c. voltage from an a.c. power source into a d.c.voltage, a reactor connected in series to one end of the power convertermeans nearer to the a.c. power source, and a short-circuiting means forshort-circuiting the a.c. power source near a zero cross point of ana.c. voltage waveform via the reactor for a first predetermined periodand immediately thereafter short-circuiting same for a secondpredetermined period shorter than the first predetermined period.

This structure also provides the effect of preventing generation ofunpleasant noise caused by short-circuiting a reactor to improve thesource power factor.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a control circuit diagram of the entirety of an airconditioner in which the first embodiment of the outdoor machine drivecontrol unit in the air conditioner according to the invention ismounted;

FIG. 2 is a flow chart showing a processing procedure corresponding toone of functions of a microcomputer which is a major component of thefirst embodiment shown in FIG. 1;

FIG. 3 is a flow chart showing a processing procedure corresponding toanother function of the microcomputer which is the major component ofthe first embodiment shown in FIG. 1;

FIG. 4 is a time chart showing relation between the stopping time andthe drive frequency corresponding to the processing procedure of themicrocomputer shown in FIG. 3;

FIG. 5 is a flow chart showing a processing procedure corresponding toanother function of the microcomputer which is the major component ofthe first embodiment shown in FIG. 1;

FIG. 6 is a graph showing relation between the temperature differenceand the drive frequency corresponding to the processing procedure of themicrocomputer shown in FIG. 5;

FIG. 7 is a time chart showing relation between the received signal andthe actual operative condition corresponding to the processing procedureof the microcomputer shown in FIG. 5;

FIG. 8 is a flow chart showing a processing procedure corresponding toanother function of the microcomputer which is the major component ofthe first embodiment shown in FIG. 1;

FIG. 9 is a control circuit diagram in the case where a secondembodiment of the outdoor machine drive control unit in an airconditioner according to the invention is mounted in an outdoor machine;

FIG. 10 is a control circuit diagram in the case where a thirdembodiment of the outdoor machine drive control unit in an airconditioner according to the invention is mounted in an outdoor machine;

FIG. 11 is a control circuit diagram in the case where a fourthembodiment of the outdoor machine drive control unit in an airconditioner according to the invention is mounted in an outdoor machine;

FIG. 12 is a flow chart showing a processing procedure corresponding toa function of a microcomputer which is a major component of the fourthembodiment shown in FIG. 11;

FIG. 13 is a time chart showing the actual operative conditioncorresponding to the processing procedure of the microcomputer shown inFIG. 11;

FIG. 14 is a control circuit diagram in the case where a fifthembodiment of the outdoor machine drive control unit in an airconditioner according to the invention is mounted in an outdoor machineof a multi-type air conditioner;

FIG. 15 is a circuit diagram showing detailed structures of ashort-circuiting device, its controller, rectifier and smoother of aninverter device, which are major components of the first to fifthembodiments of the outdoor machine drive control unit in an airconditioner according to the invention;

FIG. 16 is a waveform diagram for explaining operations of the majorcomponents shown in FIG. 14; and

FIG. 17 is a control circuit diagram of a general heat-pump-type airconditioner to which the present invention is directed.

BEST MODE FOR CARRYING OUT THE INVENTION

Explained below is the present invention in detail by way of preferredembodiments shown in the drawings.

FIG. 1 is a control circuit diagram showing the structure of the firstembodiment of an outdoor machine drive control unit in an airconditioner according to the invention, and the entirety of the airconditioner in which the unit is mounted in its outdoor machine. In FIG.1, components common to those of FIG. 17 showing the related device arelabeled with common reference numerals and their explanation is omitted.An outdoor machine drive control unit 30 is interposed in the way froman outdoor machine side connecting terminal 21 of an outdoor machine 2to a compressor 22 containing an inverter-driven three-phase brushlessmotor, outdoor fan 23 and four-way valve 25.

An indoor machine 1 has an indoor machine side connector terminal 13which includes power line connectors L, N, a first signal line connectorexclusive for transmitting ON/OFF signals for the compressor, a secondsignal line connector exclusive for transmitting ON/OFF signals for theoutdoor fan, a third signal line connector exclusive for transmittingON/OFF signals to change the four-way valve to the cooling side or theheating side, and grounding line connector E. The outdoor machine 2 hasa an outdoor machine side connector terminal 21 which includes powerline connectors L, N, a first signal line connector exclusive forreceiving the ON/OFF signals for the compressor, a second signal lineconnector exclusive for receiving the ON/OFF signals for the outdoorfan, a third signal line connector exclusive for receiving the ON/OFFsignals for the four-way valve, and grounding line connector E. And therespectively corresponding connectors of the indoor machine 1 and theoutdoor machine 2 are connected by a plurality of crossover lines 3.

The outdoor machine drive control unit 30 mainly includes ashort-circuiting device 31, an inverter device 32, photocouplers made upof a light emitting element 34A and a photo detector element 34B, lightemitting element 35A and a photo detector element 35B, a light emittingelement 36A and a photo detector element 36B, an MCU 33, a temperaturesensor 37, a relay contact 38B for supplying a drive power to theoutdoor fan 23, a relay, not shown, having a relay contact 38C forsupplying an energization power of the four-way valve 25.

Among them, the short-circuiting device 31 includes a reactor 311 and aswitching circuit 312 as explained later in greater detail, to improvethe power factor by short-circuiting the alternating current powersource near zero cross points of the waveform of the alternating currentvoltage supplied from the power line connectors L and N via the reactorfor a predetermined time. The inverter device 32 is connected to theoutput side of the short-circuiting device 31. The inverter device 32includes a rectifying circuit 321 for rectifying the a.c. voltage,smoothing capacitor 322 for smoothing the rectified pulsating flow, andan inverter main circuit 323 connecting six transistors (for example,FET) in three-phase bridges to convert a direct current to a pseudothree-phase alternating current. The inverter device 32 supplies thecompressor 22 with a single-phase alternating voltage converted into analternating current variable in frequency.

The photocoupler made up of the light emitting element 34A and the photodetector element 34B transmits the compressor ON/OFF signal received atthe first signal line connector in the outdoor machine side connectorterminal 21 to MCU 33, the photocoupler made up of the light emittingelement 35A and the photo detector element 35B transmits the outdoor fanON/OFF signal received at the second signal line connector in theoutdoor machine side connector terminal 21 to MCU 33, and thephotocoupler made up of the light emitting element 36A and the photodetector element 36B transmits the ON/OFF signal received at the thirdsignal line connector in the outdoor machine side connector terminal 21for switching the four-way valve to the cooling side or the heating sideto MCU 33.

MCU 33 is responsive to the signals transmitted from three photocouplersand a signal from an outdoor refrigerating cycle element, such astemperature sensor 37 for detecting the temperature of an outdoor heatexchanger, to control the inverter main circuit 323, relay contacts 38Band 38C and to control the short-circuiting device 31.

Explained below are operations of the first embodiment having theabove-explained structure.

When the compressor ON/OFF signal, the outdoor fan ON/OFF signal and theON/OFF signal for switching the four-way valve to the cooling side orthe heating side are transmitted from the indoor machine 1 via thecrossover lines 3 to the outdoor machine 2, these ON/OFF signals areintroduced into MCU 33. Then, MCU 33 executed processing from step 101to step 117 shown in the flow chart of FIG. 2.

That is, in step 101, MCU 33 reviews whether an ON signal has beenreceived from the first signal line for transmitting compressor ON/OFFsignals. If the signal is ON, MCU 33 controls the inverter device 32 instep 102 to gradually increase the number of revolutions of thecompressor 22, starts a timer 1 having an increase control time presettherein instep 103, and next judges in step 104 whether the preset timet_(s1) has passed or not. If MCU 33 judges that the preset time t_(s1)has passed, it next judges in step 105 whether the real number ofrevolutions of the compressor 22 has reached an allowable maximum numberof revolutions. If not, MCU 33 executes step 106. If it has reached, MCU33 executes the processing of step 108.

In step 106, MCU 33 stops the control for increasing the number ofrevolutions of the compressor 22. In the next step 107, it resets thetimer 1 and returns to step 103. In step 108, it judges whether thefirst signal line is in the OFF state or not. If judges it to be OFF, itactivates, in step 109, a timer 2 for detecting whether the OFF timereaches a preset value or not, then executes processing for reducing thenumber of revolutions of the compressor 22 by a predetermined constantvalue in step 109, and reviews whether the preset time t_(s2) of thetimer 2 has passed or not in step 111. If the time has not passed, MCU33 executes processing of step 112. If the time has passed, MCU 33executes processing of step 113. In step 112, MCU 33 judges whether thefirst signal line is in the ON condition or not, and when judging it tobe ON, it executes processing of step 103 et seq.

In step 113, MCU 33 judges whether the real number of revolutions of thecompressor 22 has reached an allowable minimum number of revolutions ornot. If it has not reached, MCU 33 resets the timer 2 in step 114, andthereafter executes the processing of step 109 et seq. If it hasreached, MCU 33 maintains the condition for a predetermined time in step115, and then judges in step 116 whether the first signal line is in theON condition or not. If MCU 33 judges the condition has become OFF, itexecutes the processing of step 103 et seq. If the line has not restoredthe ON condition, i.e., if it maintains the OFF conditions even afterdriving the compressor 22 for a predetermined time, MCU 33 stops thecompressor 22 in step 117, and terminates the processing.

When the compressor ON/OFF signal changes from the OFF state to ON stateas a result of execution of the above-explained processing by MCU 33,control is made to gradually increase the number of revolutions of thecompressor 22 and at the same time to increase it to the predeterminedmaximum number of revolutions. When the compressor ON/OFF signal changesfrom the ON condition to the OFF condition, and the OFF conditioncontinues, control is made to gradually decrease the number ofrevolutions of the compressor 22 and at the same time to graduallydecrease it to the predetermined minimum number of revolutions.Additionally, if the OFF condition is confirmed at the point of timewhere driving under the minimum number of revolutions lasts for apredetermined time, control is finished at the point of time. Further,also executed is a control for increasing or decreasing the number ofrevolutions of the compressor 22 depending on the length of the durationtime of the ON condition.

In this manner, by executing the processing shown in FIG. 2 with thestructure shown in FIG. 1, it is possible to construct an inverter-typeair conditioner by using the indoor machine 1 of a general heat-pumpsystem unchanged, mounting the above-explained outdoor machine drivecontrol unit 30 in the outdoor machine 2 and merely changing thecompressor into an inverter-driven-type compressor 22.

In the control shown in the flow chart of FIG. 2, the number ofrevolutions of the compressor is gradually increased from the minimumnumber of revolutions, for example, when driving thereof is started. Itis considered, however, that during repetition of driving and stopping,as the stopping time is the longer, the demanded power is the higher.FIG. 3 is a flow chart showing a processing procedure for changingdriving frequency at the start-up if a high power is desired, takingthat view into consideration. In this case, in step 121, MCU 33 reviewswhether the command instructs stopping or not, i.e., whether thecompressor ON/OFF signal has changed from the ON condition to the OFFcondition or not. If the command instructs stopping, MCU 33 activatesthe timer for counting the inverter stopping time in step 122, thenreviews in step 123 whether the presence or absence of a drivingcommand, i.e., whether the compressor ON/OFF signal has changed from theOFF condition to the ON condition or not, further reviews in step 124whether the stopping time t has lasted beyond the maximum preset valuet_(s3) in order to increase the driving frequency more when the time tfrom the stopping command to the driving command is longer. If the timet overpasses, MCU 33 activates the inverter under a relatively highdriving frequency f₃ in step 125. If the stopping time t is the longestpreset value t_(s3) or less, MCU investigates in step 126 whether thestopping time t has passed the intermediate preset value t_(s2). If itexceeds, MCU 33 activates the inverter under the intermediate drivingfrequency f₂ (<f₃) in step 127. If the stopping time t is theintermediate preset value ts₂ or less, MCU 33 reviews in step 128whether the stopping time t exceeds the shortest preset value t_(s1). Ifit exceeds, MCU 33 activates the inverter under the minimum drivingfrequency f₁ (<f₂) in step 129. If the stopping time t is the shortestpreset value t_(s1) or less, MCU 33 holds the drive stopping conditionin step 130, and returns to the processing of step 121. Drivingfrequencies f₃, f₂ and f₁ in this case are set in values nearer to theminimum number of revolutions than the intermediate value of the controlregion from the maximum number of revolutions to the minimum number ofrevolutions of the compressor explained above.

FIG. 4 shows a time chart at (a), (b) and (c), which shows thatrelation. If the time, from time t₀ where the stopping command isreceived to the time t where the driving command is received, is in therange of t_(S1)<t<t_(s2), then MCU 33 activates the inverter at thedriving frequency f,. If it is in the range of t_(s2)<t<t_(s3), MCU 33activates the inverter at the driving frequency of f₂. If it overpassest_(s3), MCU 33 activates the inverter at the driving frequency of f₃.

In this manner, it is possible to activate the inverter under afrequency meeting the required power by executing the processing shownin FIGS. 3 and 4 and to prevent discontinuous driving.

On the other hand, the temperature of the refrigeration cycle partsrepresented by the outdoor heat exchanger comes to largely differ fromthe preset temperature as the air conditioning load increases.Therefore, by detecting temperatures of refrigeration cycle parts andincreasing the driving frequency of the inverter for driving thecompressor so much as the difference from the preset temperature becomeslarge to decrease the temperature difference, efficient driving forbringing the room temperature closer to the preset value is enabled.

The temperature sensor 37 shown in FIG. 1 detects the temperature of theoutdoor heat exchanger as one of refrigeration cycle parts, and deliversthe detected temperature T_(j) to MCU 33. An appropriate targettemperature T_(cy) corresponding to each driving mode for cooling andheating is preset in MCU 33, and MCU 33 has the function of executingthe processing of FIG. 5 on the basis of these detected temperature Tiand the target temperature T_(cy).

That is, assume that MCU 33 judges in step 131 that the ON signal isreceived from the first signal line for transmitting the compressorON/OFF signals. Then, instep 132, MCU 33 controls the driving frequencyof the inverter device 32 to gradually increase the number ofrevolutions of the compressor 22. In step 133, it detects a temperaturedifference ΔT between the detected temperature T_(j) of the outdoor heatexchanger as one of refrigeration cycle parts and the preset targettemperature T_(cy) (ΔT=T_(cy)-T_(j) in the cooling mode andΔT=|T_(cy)-T_(j|)in the heating mode). Subsequently, in step 134, MCU 33judges whether the temperature difference ΔT is smaller than a targettemperature difference ΔT_(s0) or not. If it judges the temperaturedifference ΔT is smaller than the target temperature difference ΔT_(s0),MCU 33 stops the compressor 22 in step 135. In contrast, if it judgesthe temperature difference ΔT is equal to or larger than the targettemperature difference ΔT_(s0), MCU 33 next judges in step 136 whetherthe temperature difference ΔT is smaller than a target temperaturedifference ΔT_(s1) (>ΔT_(s0)) or not. If it judges the temperaturedifference ΔT is smaller than the target temperature difference ΔT_(s1),MCU 33 stops the control for increasing the number of revolutions of theinverter 22 in step 137, and drives the inverter device 32 at thefrequency f₁. In contrast, if it judges the temperature difference ΔT isequal to or larger than the target temperature difference ΔT_(s1), MCU33 next judges in step 138 whether the temperature difference ΔT issmaller than a target temperature difference ΔT_(s2) (>ΔT_(s1)) or not.If it judges the temperature difference ΔT is smaller than the targettemperature difference T_(s2), MCU drives the inverter device 32 at thefrequency f₂ in step 139. In contrast, if it judges the temperaturedifference ΔT is equal to or larger than the target temperaturedifference ΔT_(s1), MCU 33 drives the inverter device 32 at thefrequency of f₃ in step 140. Next, MCU 33 judges in step 141 whether theOFF signal has been received from the first signal line or not. If ithas been received, MCU 33 stops operation of the inverter device 32 tostop the compressor 22 in step 142. If it has not been received, MCU 33executes the processing of step 133 et seq.

Once these procedures are executed, the driving frequency f of theinverter device 32 changes when the temperature difference ΔT changes.FIG. 6 shows at (a) changes in driving frequency f responsive to changesin temperature difference ΔT when compressor is driven in the heatingmode, and shows at (b) changes in driving frequency f responsive tochanges in temperature difference ΔT when the compressor is driven inthe cooling mode. In any of these driving modes, a difference is madebetween values of the temperature difference ΔT while it decreases andvalues of the temperature difference ΔT while it increases so thatfrequent fluctuation in frequency be prevented. At the same time, thedriving frequency f is increased as the temperature differenceincreases, and driving is stooped when it decreases below the minimumtarget temperature difference ΔT_(s1).

In this manner, by executing the processing as explained by using FIG. 5and FIG. 6, it is possible to construct an inverter-type air conditionerby using the indoor machine of a general heat-pump system unchanged,mounting the above-explained outdoor machine drive control unit in theoutdoor machine and merely changing the compressor into aninverter-driven-type compressor.

A general heat-pump-type air conditioners drives in a defrosting mode bytransmitting ON/OFF signals to its outdoor machine such as combinationsshown at (a), (b) and (c) in FIG. 7 when it is frosted during driving inthe heating mode. MCU 33 in the outdoor machine drive control unit 30shown in FIG. 1 executes controls shown at (d), (e) and (f) in FIG. 7.

That is, in order to switch the air conditioner to the defrostingdriving mode at time t₁, the outdoor fan ON/OFF signal is changed fromthe ON condition to the OFF condition and the four-way valve ON/OFFsignal is changed from the ON condition to the OFF condition whileholding the compressor ON/OFF signal in the ON condition. On the otherhand, MCU 33 recognizes from combination of these ON/OFF signals thatthe command has changed from the heating command to the defrostingcommand, and decreases the driving frequency of the inverter heretoforedriving the compressor from f₁ to f₂ (<f₁). This is the control forpreventing that a large switching noise is generated due to fluctuationin pressure of the refrigerant when the four-way valve is switchedimmediately after the command is changed from the heating command to thedefrosting command. By this control, the pressure difference between therefrigerant discharge side and the refrigerant suction side viewed fromthe compressor. After driving the compressor 22 at the frequency f₂ fora predetermined time, MCU 33 increases the driving frequency of thecompressor from f₂ to f₃ (>f₁) at time t₂l stops the outdoor fan 23, andswitches the four-way valve 25 to the cooling side. As a result, highlyefficient defrosting driving is performed. When the command is changedfrom the defrosting command to the heating command at time t₃, MCU 33again decreases the driving frequency of the compressor from f₃ to f₂ toreduce the switching noise of the four-way valve, then returns thedriving frequency of the compressor to f₁ at time t₄ later by apredetermined time, drives the outdoor fan 23, and switches the four-wayvalve 25 to the heating side.

FIG. 8 is a flow chart showing a concrete processing procedure of MCU 33executing these controls. That is, in step 151, it judges whether theair conditioner is in the heating mode where all of the ON/OFF signalsin the first, second and third signal lines exhibit ON conditions ornot. When judging it to be in the heating mode, MCU 33 increases ordecreases the driving frequency of the compressor in response to thecondition of the outdoor fan ON/OFF signal in step 152, at the same timedrives the outdoor fan 23, and maintains the four-way valve 25 on theheating side to continue the heating drive. In step 153, MCU 33 judgeswhether the mode is the defrosting mode or not from the fact that ON/OFFsignals of the second and third signal lines among the first, second andthird signal lines have changed to the OFF conditions, i.e., the statuswhere the outdoor fan is stopped and the four-way valve is changed tothe cooling side. If it judges the mode is not the defrosting mode, itreturns to the processing of step 151. If it judges the mode is thedefrosting mode, it stores the current driving frequency of thecompressor in step 154.

Then, in step 155, it activates the timer for counting the defrostingstart time, then decreases the driving frequency of the compressor byone step in step 156, waits the preset time of the timer lapses in step157, then proceeds to the processing of step 158 to increase the drivingfrequency of the compressor to the defrosting frequency, simultaneouslystops the outdoor fan 23, and switches the four-way valve 25 to thecooling side. After that, it judges in step 159 whether the airconditioner has returned or not to the heating mode where all of theON/OFF signals in the first, second and third signal lines exhibit ONconditions. If it judges the mode is the heating mode, it activates thetimer for counting the defrosting return-back time in step 160,decreases the driving frequency of the compressor from the frequencystored just before changing to the defrosting drive by one step in step156, waits the preset time of the timer matures in step 162, thenproceed to the processing of step 163. In step 163, MCU 33 increases ordecreases the driving frequency of the compressor, depending on thecondition of the outdoor fan ON/OFF signal, at the same time drives theoutdoor fan 23, and switches the four-way valve 25 to the heating sideto change the air conditioner to the heating drive mode.

On the other hand, if MCU 33 judges in step 151 that the mode is otherthan the heating mode, it judges in step 164 whether it is the coolingmode or not. If it is the cooling mode, MCU 33 increases or decreasesthe driving frequency of the compressor depending upon the condition ofthe outdoor fan ON/OFF signal, at the same time drives the outdoor fan23, and hold the four-way valve 25 on the cooling side to continue thedriving.

In this manner, by executing the processing explained by using FIGS. 7and 8, defrosting driving similarly to that heretofore executed by aninverter-type air conditioner can be realized.

FIG. 9 is a circuit diagram in which the second embodiment of theoutdoor machine drive control unit for the air conditioner according tothe invention is mounted in the outdoor machine 2. In FIG. 9, componentscommon to those of FIG. 1 showing the first embodiment are labeled withcommon reference numerals, and their explanation is omitted. Theembodiment shown here enables two-stepped switching control of thenumber of revolutions of the outdoor fan 23, and connects between arelay contact 38B and the outdoor fan 23 a relay switching contact 38Darbitrarily movable between a H side for high speed driving and an Lside for low speed driving, so that MCU 33 controls to switch it. Byenabling two-stepped switching of the rotational speed of the outdoorfan 23, the power control range of the outdoor machine can be expandedmore.

FIG. 10 is a control circuit diagram in which the third embodiment ofthe outdoor machine drive control unit for the air conditioner accordingto the invention is mounted in the outdoor machine 2. In FIG. 10,components common to those of FIG. 1 showing the first embodiment arelabeled with common reference numerals, and their explanation isomitted. The embodiment shown here is characterized in providing twoMCUs 33A and 33B to be in charge of divisional parts of the functions ofMCU 33 shown in FIG. 1; packaging light emitting elements 34A, 35A, 36Aand photo detector elements 34B, 35B, 36B forming photocouplers, relayhaving relay contacts 38B, 38C, temperature sensor 37 and MCU 33A on asingle substrate; and assigning the function of controlling the outdoorfan 23 and the four-way valve 25 to MCU 33A, thereby to construct therefrigeration cycle controller. Additionally, by packaging MCU 33B,short-circuiting device 31 and inverter device 32 on a single substrate,and assigning the function of controlling the short-circuiting device 31and the inverter device 32 to MCU 33B, this embodiment makes up theinverter controller. MCU 33A is configured to transmit only ON/OFFsignals of the first, second and third signal lines to MCU 33B.

By dividing and assembling major components on two substrates, theembodiment is additionally effective in making it much easier to mountthem in any of various outdoor machines different in size andconfiguration.

The general heat-pump-type air conditioner can be also configured totransmit the compressor ON/OFF signal, the ON/OF signal corresponding tothe magnitude of the temperature difference between the room temperatureand the preset value, and the four-way valve ON/OFF signal from theindoor machine to the outdoor machine and to configure the outdoormachine to drive and control the compressor 22, the outdoor fan 23 andthe four-way valve 25 by modifying the outdoor machine control programalone.

FIG. 11 is a circuit diagram in which the fourth embodiment applying theinvention to an air conditioner of a system partly modifying the outdoormachine control program is mounted the outdoor machine 2. In FIG. 11,components common to those of FIG. 1 showing the first embodiment arelabeled with common reference numerals, and their explanation isomitted. The embodiment shown here is different from FIG. 1 merely inintroducing an ON/OFF signal corresponding to the magnitude of thetemperature difference between the room temperature and the preset valueas an information signal to the second signal line connector of theoutdoor machine side connector terminal 21 and hence in processingprocedure of the MCU 33.

FIG. 12 is a flow chart showing a concrete processing procedure of MCU33 shown in FIG. 11, and FIG. 13 is a time chart corresponding to theprocessing procedure of FIG. 12. In this case, MCU 33 executes theprocessing of steps 171 through 186.

That is, in step 171, MCU 33 investigates whether the ON signal has beenreceived or not from the first signal line for transmitting thecompressor ON/OFF signals. If it is in the ON condition, MCU 33 controlsthe inverter device 32 to gradually increase the number of revolutionsof the compressor 22 in step 172, starts the timer 1 preset with anincrease control time in step 173, and thereafter judges in step 174whether the preset time t_(s1) has passed or not. If it judges thepreset time t_(s1) has passed, it judges in step 175 whether the realnumber of revolutions of the compressor 22 has reached the allowablemaximum number of revolutions or not. If it has not reached, MCU 33executes the processing of step 176. If it has reached, MCU 33 executesthe processing of step 180.

In step 176, it stops the control toward increasing the number ofrevolutions of the compressor 22, then executes the processing toincrease the number of revolutions by a predetermined constant value,resets the timer 1 in the next step 177, and moves to the processing ofstep 178. In step 178, MCU 33 investigates whether the OFF signal hasbeen received from the first signal line for transmitting the compressorON/OFF signals. If the condition is the OFF condition, MCU 33 executesthe processing to stop the compressor and the outdoor fan and executedother processing. If no OFF signal has been received, MCU 33 executesthe processing of step 173 et seq.

On the other hand, if the preset time t_(s1) has not passed in step 174,or if MCU 33 judges in step 175 that the real number of revolutions hasreached the maximum number of revolutions, MCU 33 investigates in step180 whether the ON signal has been received or not from the secondsignal line. That is, it investigates whether the temperature differenceis a predetermined value or less. If it judges that the condition is theOFF condition where the temperature difference is larger than thepredetermined value, MCU 33 executes the processing of step 174 et seq.to increase the number of revolutions of the compressor. If the signalis in the ON condition, MCU 33 judges that the temperature differencebetween the preset value and the room temperature is small, thendecreases the number of revolutions of the compressor by a predeterminedvalue (by two steps of the increasing unit) in step 181, andsubsequently starts the timer 2 for counting the ON condition time instep 182.

In the next step 183, it judges whether the condition of the secondsignal line is the OFF condition or not. If it is the ON condition,i.e., if the temperature difference is large, MCU 33 executes theprocessing of step 177 by increasing the number of revolutions of thecompressor by one step in step 184. On the other hand, if it judges thatthe condition of the second signal line is the ON condition in step 183,i.e., if it judges that the temperature difference is small, MCU 33judges in step 185 whether the preset time t_(s2) of the timer 2 haspassed or not. If it has passed, MCU 33 decreases the number ofrevolutions of the compressor by one step in step 186, and returns tothe processing of step 183. That is, it executes the processing forreducing the number of revolutions of the compressor by one step everytime when the preset time of the timer 2 passes.

As a result of the above-explained processing executed by MCU 33, whenthe compressor ON/OFF signal changes from the OFF condition to the ONcondition, the control of gradually increasing the number of revolutionsof the compressor 22 is done, and at the same time, the control forincreasing it to the predetermined maximum number of revolutions isdone. Additionally, when the compressor ON/OFF signal changes from theON condition to the OFF condition, MCU 33 stops the control of thecompressor 22 and the outdoor fan 23, and stops the air conditioningcontrol. Further, when it detects from the condition of the ON/OFFsignal from the second signal line corresponding to the temperaturedifference that the difference between the room temperature and thepreset temperature is not larger than the predetermined value, itexecutes the control for reducing the number of revolutions of thecompressor by a predetermined value. After that, when it detects thatthe difference between the room temperature and the preset temperatureis larger than the predetermined value, it controls to increase thenumber of revolutions of the compressor by a predetermined value.

FIG. 14 is a circuit diagram in which the fifth embodiment of theoutdoor machine drive control unit of the air conditioner according tothe invention is mounted in the outdoor machine of a multi-type airconditioner. In FIG. 14, components common to those of FIG. 1 showingthe first embodiment are labeled with common reference numerals, andtheir explanation is omitted. Here are two indoor machines 1A and 1B areconnected to a single outdoor machine 2. The outdoor machine 2 includesa first outdoor machine side connector terminal 21A for connectingsignal lines of the indoor machine 1A, and a second outdoor machine sideconnector terminal 21B connecting signal lines of the indoor machine 1B.The outdoor machine drive control unit 30 is configured to inputrespective signal to MCU 33 via photocouplers, of which the number iscorresponding to that of the signal line connectors in the outdoormachine side connector terminals 21A and 21B. In this case, MCU 33 makescomputation of the air conditioning load in response to the ON/OFFconditions of the signals in respective signal line connectors, andexecutes the processing substantially equal to that of FIG. 2 in ageneral view.

In this manner, with the structure shown in FIG. 14, it is possible toconstruct an inverter-type air conditioner by using the indoor machineof a general heat-pump system unchanged, mounting the above-explainedoutdoor machine drive control unit in the outdoor machine and merelychanging the compressor into an inverter-driven-type compressor.

FIG. 15 is a circuit diagram showing a detailed structure of theshort-circuiting device 31, its controller, rectifier and smoother ofthe inverter device 32 shown in the foregoing embodiments. In therectifier circuit 321, a serially connected circuit of diodes D, D₂ anda serially connected circuit of diodes D₃, D₄ are connected in parallel,a serially connected circuit of capacitors C₁, C₂ is further connectedin parallel, and an inter-connection point of the capacitors C₁, C₂ isconnected to the inter-connection point of the diodes D₃, D₄.

On the other hand, the short-circuiting device 31 includes a reactor 311and a switching circuit 312. One of the reactor 311 is connected to thepower line connector L in the outdoor machine side connector terminal21, and the other end of the reactor 311 is connected to theinter-connection point of the diodes D₁, D₂ forming the rectifiercircuit 321. Consequently, the power line connector N in the outdoorside connector terminal 21 is connected to the inter-connection point ofthe diodes D₃, D₄. The switching circuit 312 includes a seriallyconnected circuit of diodes D₅ and D₆ and a serially connected circuitof diodes D₇ and DB, which are connected in parallel to form a diodebridge circuit. Among them, the inter-connected point of the diodes D₅and D₆ is connected to the load side of the reactor 311, and theinter-connected point of the diodes D₇ and D₈ is connected to the powerline connector N. Further, at opposite ends of the parallel connectionof the serially connected circuit of the diodes D₅ and D₆ and theserially connected circuit of the diodes D₇ and D₈, collector andemitter of a transistor T are connected.

For the purpose of ON/OFF control of the transistor T, a zero crossdetector means 51, drive signal generating means 52 and short-circuitelement drive means 53 are provided. Among them, the zero cross detectormeans 51 may be a photocoupler or a current transducer, for example, andit is configured to detect a zero point of an a.c. voltage and supply adetected signal to the drive signal generating means 52. A function ofthe drive signal generating means 52 is realized by the MCU 33, and itis configured to generate a power factor improving pulse and a noisereducing pulse having a width much smaller than the power factorimproving pulse and to deliver them to the short-circuit element drivemeans 53. The short-circuit element drive means 53 are responsive tothese power factor improving pulse and noise reducing pulse to turn thetransistor T ON and thereby short-circuit the a.c. source via theswitching circuit 312.

Explained below are operations of the short-circuiting device 31, itscontroller, rectifier and smoother of the inverter device 32 shown inFIG. 15 with reference to the waveform diagram of FIG. 16. When an a.c.voltage of 100 V is supplied between the power line connectors L and N,the a.c. voltage undergoes voltage doubling rectification and smoothingby a voltage doubling rectifying circuit made up of the diodes D₁, D₂,capacitors C₁, C₂ and smoothing capacitor 322. That is, in the durationwhere the power line connector L is positive relative to the power lineconnector N, a current flows in the route of power line connectorL→reactor 311→diode D₁→capacitor C₁. →power line connector N, and thecapacitor C₁ is charged thereby. In the duration where the power lineconnector N is positive relative to the power line connector L, acurrent flows in the route of power line connector N→capacitor C₂→diodeD₂→reactor 311→power line connector L, and the capacitor C₂ is chargedthereby. Therefore, the smoothing capacitor 322 is charged by the sumvoltage of the voltage across the opposite ends of the capacitor C, andthe voltage across the opposite ends of the capacitor C₂, and a d.c.voltage of approximately 280 V is supplied to the subsequent invertermain circuit 323.

The diode D₃ forming the rectifier circuit 321 makes up a dischargecircuit for preventing the capacitor C₁ from being charged in theopposite polarity during initial charge of the capacitor C₂. Similarly,the diode D₄ form a discharge circuit for preventing the capacitor C₂from being charged in the opposite polarity during initial charge of thecapacitor C₁.

At that time, an a.c. voltage having a sinusoidal waveform as shown bynumeral 61 in FIG. 16 is supplied between the power line connectors Land N. The zero cross detector means 51 detects a zero cross point wherethe a.c. voltage is zero. The drive signal generating means 52 is drivenby the detected signal.

When driven by the zero point detection signal from the zero crossdetector means 51, the drive signal generating means 52 generates apower factor improving pulse 64 a and a noise reducing pulse 64 b, bothshown in FIG. 16, after passing the zero point of the a.c. source. Inresponse to the power factor improving pulse 64 a and the noise reducingpulse 64, the short-circuit element drive means 53 turn the transistor TON. As a result, not only expanded is the source current supply period,but also improved is the power factor. Additionally, when theshort-circuit element drive means 53 turns the transistor T ON inresponse to the noise reducing pulse 64 b, it is possible to reducenoise upon removal of the short-circuiting current as a result ofcanceling the short circuit of the reactor 311.

More specifically, with respect to the source current waveform beforeimprovement of the power factor as shown by numeral 62 in FIG. 16, thesource current waveform after improvement of the power factor by thepower factor improving pulse 64 a is expanded in source current supplyperiod as shown by numeral 63, and this shows that the source powerfactor is certainly improved. Then, by outputting the noise reducingpulse 64 b having a very small pulse width subsequently to the powerfactor improving pulse 64 a , unpleasant noise sounding “zee” generatedfrom the reactor upon removal of the short-circuiting current as aresult of short-circuiting the reactor 311 can be reduced withoutsubstantially no adverse affection to the source current waveform andthe source power factor.

It is also acceptable to generate the power factor improving pulse 64 aand the noise reducing pulse 64 b in the opposite sequence.Alternatively, if the noise reducing pulse 64 is generated twice beforeand after the power factor improving pulse 64 a, noise can be reducedmore reliably. Each of the power improving pulse 64 a and the noisereducing pulse 64 b need not be a single pulse. For example, it is alsoacceptable to generate two noise reducing pulses 64 b before or afterone power improving pulse 64 a, or to generate one or more noisereducing pulses 64 b before or after two consecutive power factorimproving pulses 64 a.

As explained above, by incorporating the short-circuiting meansexplained with reference to FIG. 15 and FIG. 16 in the outdoor machinedrive control unit 30, the source power factor is improved, andunpleasant noise caused by short-circuit of the reactor is prevented.

Industrial applicability as apparent from the foregoing description, theoutdoor machine drive control unit of an air conditioner according tothe invention can construct an inverter-type air conditioner by using ageneral heat-pump-type indoor machine unchanged and merely mounting itin an outdoor machine.

What is claimed is:
 1. An outdoor machine drive control unit for an airconditioner of a separate type having a signal line connector providedin an outdoor machine to receive an ON/OFF signal for a compressorexclusively, comprising: an inverter device for supplying saidcompressor with power variable in frequency; and a control device forcontrolling said inverter device to gradually increase the number ofrevolutions of said compressor when said ON/OFF signal for thecompressor received through said signal line connector changes from theOFF condition to the ON condition.
 2. The outdoor machine drive controlunit for an air conditioner according to claim 1 wherein said controldevice has the function of controlling said inverter device to graduallydecrease the number of revolutions of said compressor.
 3. The outdoormachine drive control unit for an air conditioner according to claim 1wherein said control device has the function of controlling saidinverter device to decrease the number of revolutions of said compressorto a minimum number of revolutions which is lower than a preset numberof revolutions by a predetermined value.
 4. The outdoor machine drivecontrol unit for an air conditioner according to claim 3 wherein saidcontrol device makes the number of revolutions of said compressor todecrease gradually when it makes same to decrease to said minimum numberof revolutions.
 5. The outdoor machine drive control unit for an airconditioner according to claim 1 wherein said control device includes apower converter means for converting an a.c. voltage from an a.c. powersource into a d.c. voltage, a reactor connected in series to one end ofsaid power converter means nearer to said a.c. power source, and ashort-circuiting means for short-circuiting said a.c. power source neara zero cross point of an a.c. voltage waveform via said reactor for apredetermined period.
 6. The outdoor machine drive control unit for anair conditioner according to claim 1 wherein said control deviceincludes a power converter means for converting an a.c. voltage from ana.c. power source into a d.c. voltage, a reactor connected in series toone end of said power converter means nearer to said a.c. power source,and a short-circuiting means for short-circuiting said a.c. power sourcenear a zero cross point of an a.c. voltage waveform via said reactor fora first predetermined period and immediately thereafter short-circuitingsame for a second predetermined period shorter than said firstpredetermined period. 7.An outdoor machine drive control unit for an airconditioner of a separate type having a signal line connector providedin an outdoor machine to receive an ON/OFF signal for a compressorexclusively, comprising: an inverter device for supplying saidcompressor with power variable in frequency; and a control device forcontrolling said inverter device to increase the number of revolutionsof said compressor to a preset number of revolutions when said ON/OFFsignal for the compressor received through said signal line connectorchanges from the OFF condition to the ON condition.
 8. An outdoormachine drive control unit for an air conditioner of a separate typehaving a signal line connector provided in an outdoor machine to receivean ON/OFF signal for a compressor exclusively, comprising: an inverterdevice for supplying said compressor with power variable in frequency;and a control device including a timer means for cumulatively countingthe duration of time of the ON condition after said ON/OFF signal forthe compressor changes from the OFF condition to the ON condition so asto increase or decrease the number of revolutions of said compressordepending on the length of said duration of time of the ON condition. 9.An outdoor machine drive control unit for an air conditioner of aseparate type having a signal line connector provided in an outdoormachine to receive an ON/OFF signal for a compressor exclusively,comprising: an inverter device for supplying said compressor with powervariable in frequency; and a control device including a timer means forcumulatively counting the duration of time of the OFF condition sincesaid ON/OFF signal for the compressor changes from the OFF condition tothe ON condition until returning to the ON condition, so as to increaseor decrease the number of revolutions of said compressor after returningto the ON condition, depending on the length of said duration of time ofthe OFF condition.
 10. The outdoor machine drive control unit for an airconditioner according to claim 9 wherein said control device controlssaid inverter device to increase the number of revolutions of saidcompressor when said duration of time of the OFF condition exceeds apreset value.
 11. The outdoor machine drive control unit for an airconditioner according to claim 10 wherein said preset value includes aplurality of values different in magnitude.
 12. An outdoor machine drivecontrol unit for an air conditioner of a separate type having a signalline connector provided in an outdoor machine to receive an ON/OFFsignal for a compressor exclusively, comprising: an inverter device forsupplying said compressor with power variable in frequency; atemperature sensor for detecting temperature of a refrigeration cyclecomponent provided in said outdoor machine; and a control device forcontrolling said inverter device to increase or decrease the number ofrevolutions of said compressor in response to the temperature of therefrigeration cycle component detected by said temperature sensor whenthe ON/OFF signal for the compressor exhibits the ON condition.
 13. Theoutdoor machine drive control unit for an air conditioner according toclaim 12 wherein said control device controls said inverter device todecrease the difference between the detected temperature of therefrigeration cycle component and a preset reference temperature.
 14. Anoutdoor machine drive control unit for an air conditioner of a separatetype having a first signal line connector for receiving an ON/OFF signalfor a compressor exclusively, a second signal line connector forreceiving an ON/OFF signal for an outdoor fan exclusively, and a thirdsignal line connector for receiving an ON/OFF signal for switching afour-way valve to a cooling side or a heating side exclusively, whichare provided in an outdoor machine, comprising: an inverter device forsupplying said compressor with power variable in frequency; and acontrol device including a microcomputer for controlling outputfrequency of said inverter device, driving or stopping of said outdoorfan and switching of said four-way valve in response to a combination ofON/OFF conditions of said ON/OFF signals received by said first, secondand third signal line connectors.
 15. The outdoor machine drive controlunit for an air conditioner according to claim 14 wherein, when theON/OFF signal for the compressor exhibits the ON condition, the ON/OFsignal for the outdoor fan exhibits the ON condition, and the ON/OFFsignal for the four-way valve changes from the heating side to thecooling side, said control device controls said inverter device toincrease the number of revolutions of said compressor to a preset numberof revolutions for defrosting driving.
 16. The outdoor machine drivecontrol unit for an air conditioner according to claim 15 wherein, whenthe ON/OFF signal for the compressor exhibits the ON condition and theON/OFF signal for the four-way valve returns from the cooling side tothe heating side, said control device controls said inverter to drivesaid compressor for a predetermined time under a number of revolutionslower than the number of revolutions thereof before the ON/OFF signalfor the four-way valve changes from the heating side to the coolingside, and to change said four-way valve from the cooling side to theheating side after driving said compressor for said predetermined timeunder the low number of revolutions.
 17. The outdoor machine drivecontrol unit for an air conditioner according to claim 14 wherein saidcontrol device includes a first microcomputer for controlling saidinverter device exclusively, and a second computer connected to saidfirst, second and third signal line connectors to transmit controlsignals to a four-way valve driving device, an outdoor fan drivingdevice and said first microcomputer in accordance with ON/OFF signalreceived through said signal line connectors.
 18. The outdoor machinedrive control unit for an air conditioner according to claim 14 whereinsaid outdoor machine includes a plurality of sets of signal lineconnectors, each set including said first, second and third signal lineconnectors, and said control device controls output frequency of saidinverter device, driving or stopping of said outdoor fan and switchingof said four-way valve in response to a combination of ON/OFF conditionsof said ON/OFF signals through said first, second and third signal lineconnectors.
 19. An outdoor machine drive control unit for an airconditioner of a separate type having a first signal line connector forreceiving an ON/OFF signal for a compressor exclusively, a second signalline connector for receiving an ON/OFF signal indicating whether thedifference of said room temperature from a preset temperature is largerthan a predetermined value or not, and a third signal line connector forreceiving an ON/OFF signal for switching a four-way valve to a coolingside or a heating side exclusively, which are provided in an outdoormachine, comprising: an inverter device for supplying said compressorwith power variable in frequency; and a control device including amicrocomputer for controlling driving or stopping of said outdoor fan,switching of said four-way valve and said inverter device in response toa combination of ON/OFF conditions of said signals received by saidfirst, second and third signal line connectors.
 20. The outdoor machinedrive control unit for an air conditioner according to claim 19 whereinsaid control device decreases the number of revolutions of saidcompressor by a predetermined value when it is detected from the ON orOFF condition of the signal through said second signal line connectorthat the difference of the room temperature from the preset temperatureis not larger than said predetermined value.
 21. The outdoor machinedrive control unit for an air conditioner according to claim 19 whereinsaid control device decreases the number of revolutions of saidcompressor by a predetermined value when it is detected from the ON orOFF condition of the signal through said second signal line connectorthat the difference of the room temperature from the preset temperatureis not larger than said predetermined value, and thereafter increasesthe number of revolutions of said compressor by a predetermined valuewhen it is detected from the ON or OFF condition of the signal throughsaid second signal line connector that the difference of the roomtemperature from the preset temperature is larger than saidpredetermined value.
 22. The outdoor machine drive control unit for anair conditioner according to claim 19 wherein said control devicedecreases the number of revolutions of said compressor by a firstpredetermined value when it is detected from the ON or OFF condition ofthe signal through said second signal line connector that the differenceof the room temperature from the preset temperature is not larger thansaid predetermined value, and thereafter increases the number ofrevolutions of said compressor by a second predetermined value smallerthan said first predetermined value when it is detected from the ON orOFF condition of the signal through said second signal line connectorthat the difference of the room temperature from the preset temperatureis larger than said predetermined value.